The two-year review of the company’s policies and practices involved interviewing and gathering the concerns of over 100 civil rights organisations, as well as advocates and members of Congress.

The auditors were concerned about Facebook’s commitment to “protect a particular definition of free expression”, beginning with a speech from chief executive Mark Zuckerberg in 2019. The report said: “Elevating free expression is a good thing, but it should apply to everyone.”

The audit praised some actions taken by Facebook to advance the civil rights of its users, including stopping advertisers running ads for housing, employment and credit to target users by age, gender or zip code.

It also highlighted the social network’s expansion of its voter suppression policies since the review began in 2018, and its creation of a policy on census interference.

However, Facebook’s decision not to take action over three statements from Donald Trump in May this year “caused considerable alarm for the auditors and the civil rights community,” the report said. “These decisions exposed a major hole in Facebook’s understanding and application of civil rights.”

Facebook commissioned the review in May 2018. The report, authored by Laura Murphy and Megan Cacace, encouraged the company to consider, debate and make changes on its various recommendations, particularly in relation to expanding its internal civil rights infrastructure.

Sheryl Sandberg, chief operating officer at Facebook, said in a statement on the company’s website: "This audit has been a deep analysis of how we can strengthen and advance civil rights at every level of our company — but it is the beginning of the journey, not the end. What has become increasingly clear is that we have a long way to go. As hard as it has been to have our shortcomings exposed by experts, it has undoubtedly been a really important process for our company. We would urge companies in our industry and beyond to do the same."

Sandberg said Facebook had "made significant progress" on areas highlighted during the audit process and added: "While we won't be making every change [the auditors] call for, we will put more of their proposals into practice."